Interlock circuit protector



J. LEB'OVICI.

INTERLOCK CIRCUIT PROTECTOR.

APPLICATION FILED APR.26, I919.

1,422, 1 10, f Patented July 11,1922.

UNITED STATES PATENT OFFICE.

JUSTIN LEBOVICI, OF OAKLEY, OHIO, ASSIGNOR-TO THE TRIUMPH ELECTRIC GOM- PANY, A CORPORATION OF OHIO.

INTERLOCK CIRCUIT PROTECTOR.

' 4 Application filed April 26,

To all whom it may concern:

Be it known that I, JUs'r1N LEBOVICI, a citizen of the United States, residing at Oakley, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Interlock Circuit Protectors, of which the following is a specification. A

This invention relates to overload circuit protectors and particularly to such protectors for use where a plurality of circuits or. lines are to be simultaneously broken by an overload in any one of their number.

In polyphase circuits including 'a polyphase induction. motor, for instance, the blowing of a fuse in one phase 1s a decided menace to the connected apparatus if the other lines are not simultaneously opened; for it leaves the motor thrown across two lines in whichcondition it will burn out unless a fuse or other circuit breaker of a second phase acts in time to prevent it.

The object of this invention is to provide a circuit protector combining with two or more lines or circuits whereby the lines areso related that an overload breaking the circuit in one line with automatically and simultaneously interrupt other lines and disconnect the lead. A further object of the invention is to make this interrupting action sure and instantaneous by normally maintaining circuit opening forces in one line balanced against operation by a circuit breaking element of another line so that overload actuation of the latter will break the circuits of both lines.

In the accompanying drawings, Fig. 1 is a vertical section through one embodiment of the invention.

Fig. 2 is a side elevation of the same, Fig." 3 is a diagram illustrating one embodiment of this invention applied to a polyphase circuit, and

Fig. 4. is a view similar to Fig. 3 illustrata modification.

in Y In the embodiment of the invention illustrated in Figs. 1 and 2 a fuse box 5 is provided with terminals 6 and 7 for one line and terminals 8 and 9 for another line which is to be broken simultaneously with the first line in case the first line is overloaded. The first line circuit passes through terminals 6 and 7, flexible conductors 10 and 11, fuse blocks 12 and 13, and fuse 15 fastened be- Specification of Letters Patent: I Patented July 11, 192 2.

1919. Serial No.'292,976.

tween said blocks. The blocks 12 and 13 are pivotally mounted in the casing 5 at 16 and 17 respectively and resiliently pressed apart by springs 18 and 19 so that when the connecting fuse 15 melts or blows the blocks 12 and 13 will move apart. Fuse blocks 12 and 13 are insulated from their pivoted supporting blocks.

When the blocks 12 and 13 are held together by fuse 15 the inclined surfaces 20, 21 of the blocks serve to press the switch bar 23 to the left (Fig. 1) to hold its leaf spring switch 24 across contacts 25 and 26 of the terminals 8 and 9 to close the circuit of the second line. The switch 23, 24 is guided on the fiber tube 27 supported on the bolt 28 and is pressed open away from the contacts 25, 26 by coil spring 29. between the switch 24 and the side of the box 5.v The front of box 5 is'open and is provided with a transparent cover 30 and cover retaining rim 31. Should the fusible element 15 break the circuit through terminals 6, 7 rings 18 and 19 will spread fuse blocks 12 and 13 permitting the spring 29 to open switch 24 and break the circuit bet-ween terminals 8 and 9. When the cause of the'overload has been remedied the apparatus is reassembled in protective position by removing cover 30, closing switch 24 fastening anew fuse 15 between blocks 12, 13, as by screws 32, and replacing the cover 30 and its retaining rim 31.

The application of thisv invention to a three-phase induction motorcircuit is illustrated in diagram in Fig. 3, in connection are connected through fuses F F F to supply lines a, b, 0, each line circuit including a gap G G G controlled by one of the other fuses, the rotor secondary of the motor being indicated at R. Upon any of the circuit openers or fuses F, F F being overloaded so as to break the respective circuit, a sp-rin S S or S will raise the corresponding lse block L, L or L and with it the switch T, T or T to break the gap G G or G of another phase circuit and thus two phases of three being open the motor is operatively and safely disconnected from the line.

In Fig. 4 a circuit protector showing one embodiment of this invention. is illustrated I in connection with a polyphase circuit and with a switch having a no voltage release. In this system each phase primary A, B, C is connected to its corresponding linen, b, 0, through a fuse F F F and the circuit in series with a suitable source of current X and the no voltage release V passes through gaps G, G", (i so that when any one of the fuses F F F blows, the, spring 3, S or S will open the correspondlng gap G, G or G and this in turn will act upon the no voltage release V which. will drop its core on arm m to turn shaft h totip up arms 12,, n n, and rmit the toggles below switches IV WV W to collapse and trip open all the switches simultaneously and disconnect the motor lines A, B and C from the supply lines.

In the embodiments of this invention shown and described the interlocking circuit is held closed by tension on the circuit breaking element of the overload circuit and the pressure of the parts continually tends to open both circuits, the breaking of-the overload and interlocking'circ-uits is made certain at any excess load and practically simultaneous so as to prevent the blowing of asecond fuse and both the circuits are maintalned open until intentionally closed. In the embodiments shown the protector of this invention is simple in structure, sure in operation, and easily wired into a variety of combinations of circuits. The invent-ion may be applied to single phase and direct current systems to open both sides of the line simultaneously and it is obvious that electromagnetic or other forms of circuit breaking elements may be used in place of the fuses shown and described.

I claim 1. The combination with a polyphase circuit of means for breaking the circuit of one phase by the breaking of a circuit of another phase comprising an independently openable circuit breaker element in' the circuit respectively of each phase adapted to be controlled by a predetermined current in its circuit, a second circuit breaking element respectively in the circuit of each phase resiliently pressed in a direction to open the circuit of its respective phase, and each of said second circuit breaking elements being openable independently of each other, and means whereby the opening pressure on each .of said second circuit breaking elements is pendently of each other, the first named elements of each phase being in series respectively with the second named elements of each phase, and means for causing the opening of one ofsaid second named elements upon the, opening of one of said first named elements in a different phase.

3. The combination with a polyphase circuit of a circuit breaking element in the circuit of each of said phases respectively and openable independently of each other, a secondcircuit breaking element in the circuit of each of said phases respectively and openable independently of each other, each of said second circuit breaker elements being biased to move to open position,- and means whereby each of said second circuit breaking elements is held in closed position respectively by one of said first named circuit breaking elements connected in a diiferent phase of the circuit.

4. The combination with a polyphase circuit of a circuit breaking element in the circuit of each of said phases respectively and openable independently of each other upon the passage of an overload current, a second circuit breakingvelement in the circuit of each of said phases respectively and openable independently of each other, each of said second circu t breaker elements being biased to move to open position, and means whereby each of said second circuit breaking elements is held in closed position respectivel by one of said first named circuit brea in elements connected in a different phase 0% the circuit.

5. The combination with a polyphase circuit of a circuit protector adapted to open the circuit of one phase by a predetermined current in the circuit of another phase, comprising oppositely movable fuse blocks, a fuse holding said blocks together, a switch member retained in one position by said blocks in held position, and means for movifng said switch member on melting of said use.

6. The combination with a circuit protector adapted to open the circuit of one phase by a predetermined current in the circuit of another phase comprising a pair of fuse blocks yieldably forced apart, a fuse holding said blocks toward each other, a switch member retained in closed position by said blocks in held position, and means moving said switch member and said blocks to open said blocks and switch member upon melting of said fuse.

7. The combination with a polyphase circuit of a fuse in the circuit of each of said phases respectively, a circuit breaking element in the circuit of each of said phases respectively and openable independently of each other, said circuit breaking elements being biased to move to open position, and means whereby the fuse of each circuit reto move to open osltion, and means whereby the fuse of eac circuit respectively holds in closed position one of said circuit breakin elements connected in the phase of anot er circuit.

9. In a circuit protector adapted to open one circuit by a predetermined current in another circuit, the combination with pivoted fuse blocks having inclined surfaces, a

switch member in one circuit engaging said 20 surfaces to press said fuse blocks apart, and a fuse in another circuit holding said-blocks against separation.

. JUSTIN LEBOVICI. 

